Technical Abstract:
American potato bean (Apios americana Medikus) is a nitrogen-fixing perennial leguminous vine that is native to the eastern half of the United States. In the wild, the plant prefers moist soils near bodies of water and full sunlight for at least part of the day. It grows well in waterlogged, acidic, sandy soils, where conventional legumes have difficulty growing. The plant grows fast in summer, a good characteristic of forage crops. The nutritional and feeding values of American potato bean herbage have not been reported. We obtained 40 accessions from an American potato bean collection made at Louisiana State University by Dr. William J. Blackmon and collaborators and planted them as an observation trial in 2006. Plots were six feet long, each planted with two tubers. Accessions showed wide ranges in herbage fresh weight (0.35–2.95 lb/plot), tuber fresh weight (0.15–0.99 lb/plot), number of tubers (3–94/plot), and individual tuber fresh weight (0.01–0.07 lb/tuber). Feed analysis of herbage (leaves and stems) of 33 accessions gave also wide ranges for crude protein (15.4–22.8 %), acid detergent fiber (26.7–41.6 %), neutral detergent fiber (37.2–46.2 %), total digestible nutrients (55.1–72.1 %), K (1.19–1.96 %), Ca (1.63–3.35 %), Fe (238–1551 %), Zn (20–339 %), and relative feed value (122–166). This variability should allow the selection of superior accessions for forage production. We have observed deer feeding on the foliage of this plant in early fall, when grasses and tree twigs and leaves are still plentiful, a strong indication that American potato bean is palatable to other browsing ruminants such as goats and sheep.